“The greatest roadblock to solving a problem is the human mind,” he tells audiences.

Brown, a North Dakota farmer who favors baseball caps and red-striped polo shirts, is not talking about disruptive technology start-ups, political causes, or the latest self-help fad. He is talking about farming, specifically soil-conservation farming, a movement that promotes leaving fields untilled, “green manures” and other soil-enhancing methods with an almost evangelistic fervor.

Such farming methods, which mimic the biology of virgin land, can revive degenerated earth, minimize erosion, encourage plant growth and increase farmers’ profits, their proponents say. And by using them, Brown told more than 250 farmers and ranchers who gathered at the hotel for the first Southern Soil Health Conference, he has produced crops that thrive on his 5,000-acre farm outside of Bismarck, N.D., even during droughts or flooding.

He no longer needs to use nitrogen fertilizer or fungicide, he said, and he produces yields that are above the county average with less labor and lower costs.

“Nature can heal if we give her the chance,” Brown said.

Neatly tilled fields have long been a hallmark of American agriculture and its farmers, by and large traditionalists who often distrust practices that diverge from time-honored methods. But soil-conservation farming is gaining converts as growers increasingly face extreme weather, high production costs, a shortage of labor and the threat of government regulation of agricultural pollution.

Farmers like Brown travel the country telling their stories, and organizations like No-Till on the Plains — a Kansas-based nonprofit devoted to educating growers about “agricultural production systems that model nature” — attract thousands.

“It’s a massive paradigm shift,” said Ray Archuleta, an agronomist at the Natural Resources Conservation Service, part of the federal Agriculture Department, which endorses the soil-conservation approach.

Government surveys suggest that the use of no-tillage farming has grown sharply over the last decade, accounting for about 35 percent of cropland in the United States.

For some crops, no-tillage acreage has nearly doubled in the last 15 years. For soybeans, for example, it rose to 30 million acres in 2012 from 16.5 million acres in 1996. The planting of cover crops — legumes and other species that are rotated with cash crops to blanket the soil year-round and act as green manure — has also risen in acreage about 30 percent a year, according to surveys, though the total remains small.

Farmers till the land to ready it for sowing and to churn weeds and crop residue back into the earth. Tilling also helps mix in fertilizers and manure and loosens the top layer of the soil.

But repeated plowing exacts a price. It degrades soil, killing off its biology, including beneficial fungi and earthworms, and leaving it, as Archuleta puts it, “naked, thirsty, hungry and running a fever.”

Degraded soil requires heavy applications of synthetic fertilizer to produce high yields. And the soil washes away easily in heavy rain, taking nitrogen and other pollutants with it into rivers and streams.

Soil health proponents say that by leaving fields unplowed and using cover crops, which act as sinks for nitrogen and other nutrients, growers can increase the amount of organic matter in their soil, making it better able to absorb and retain water.

“Each 1 percent increase in soil organic matter helps soil hold 20,000 gallons more water per acre,” said Claire O’Connor, a staff lawyer and agriculture specialist at the Natural Resources Defense Council.

In turn, more absorbent soil is less vulnerable to runoff and more resistant to droughts and floods. Cover crops also help suppress weeds. Environmental groups like the Defense Council have long been fans of soil-conservation techniques because they help protect waterways and increase the ability of soil to store carbon dioxide, rather than releasing it into the air, where it contributes to climate change.

But the movement also has critics, who argue that no-tillage and other methods are impractical and too expensive for many growers.

Tony J. Vyn, a professor of agronomy at Purdue, said the reasons growers cite for preferring to fully till their fields vary depending on geography, the types of crops they grow and the conditions of their soil. But they include the perception that weed control is harder using no-tillage; that the method, which reduces water evaporation, places limits on how early in the year crops can be planted; and that the residue left by no-tilling is too difficult to deal with, especially when corn is the primary cash crop.

Even farmers who enthusiastically adopt no-till and other soil-conservation methods rarely do so for environmental reasons; their motivation is more pragmatic.

“My goal is to improve my soil so I can grow a better crop so I can make more money,” said Terry McAlister, who farms 6,000 acres of drought-stricken cropland in North Texas. “If I can help the environment in the process, fine, but that’s not my goal.”

McAlister said that he switched to no-tillage in 2005, when an agricultural economist calculated that the method offered a $15-per-acre advantage over full tilling.

Now he is a convert. Standing in a field of winter wheat, he pointed proudly at the thick blanket of stubble sprinkled with decaying radishes and turnips. “One of the toughest things about learning to do no-till is having to unlearn all the things that you thought were true,” he said.